NASA's Curiosity Rover, the $2.5bn robot which was launched towards Mars in November 2011, has found clear evidence that at one point there was liquid running water on the surface of Mars. This discovery is a significant step towards ascertaining whether the Red Planet, our nearest planetary neighbour, was ever capable of sustaining life.
Channels on the surface of Mars which appeared to have been cut as a result of some sort of flow have been observed many times, and it was assumed that the so-called canals of Mars had indeed been shaped by liquid water. But this conjecture has been given added credence by the observation of classic conglomerates, according to the BBC. Conglomerates, as the name suggests, are rocks made up of smaller rocks - gravel and sand. Pebbles in these conglomerates are of a size and shape that suggests to scientists that they were picked up, transported, and eroded in liquid water.
It is thought that the rover has stumbled across a network of streams - researchers suggested that the rocks themselves could have been deposited on the streambed up to "several billion" years ago, but that the streams themselves might have persisted until much, much later.
Scientists are now studying the size and shape of the rocks to see to what extent they can determine the probable speed and distance of the ancient water flow. Later they also want to study the chemical composition of the rocks to see whether they can draw any conclusions about the PH number of the water, which could give some clues about the nature of the environment at the time water was still flowing on the surface of Mars.
These streams, in Gale Crater where the Curiosity Rover landed just seven weeks ago, are between the northern rim of the crater and the huge mountain in the crater's centre. Scientists even believe they have identified the likeliest source of the water in the crater's rim, a valley that they have named Peace Vallis. Their hypothesis is that the conglomerates are part of an alluvial fan of material that washed across the crater's plain, cutting a network of many individual streams.
This discovery might seem to just confirm what scientists already suspected, but it is nonetheless a key step in Curiosity's two year mission to determine whether microbial life could ever have existed on Mars, or even whether it still persists under the surface of the barren Red Planet.